E-mu Emulator II+ screen replacement

About a year ago, I bought an Emulator II+, working but with some known (and, as it turned out, some unknown) issues. One was a hard-to-read display thought to be a due to a fading backlight. Well, the backlight was certainly dim, so I ordered a suitable replacement from Farnell. I turned out to be about 1cm too short. So I ordered a much larger EL foil and cut it to size.

Success! Except that the backlight was only part of the problem - the LCD itself had become very faint. Nevermind, I thought, it's a 16 x 2 display with an interface that is meant to be pretty standard, so I ordered a modern replacement. It was certainly bright, but it also was decidedly flakey, with random characters appearing from time to time.

So, time to replace like-for-like. Except the part is so unpopular today that component suppliers aren't interested unless you want to order at least 300 of them. And E-mu Emulator IIs were a low volume product, so its not like there's a huge market out there for specialist part suppliers.

Luckily, the E-mu SP1200 drum machine was much more popular (and is also, apparently, still fairly sought after by some Hip Hop producers) and its a 100% identical part. Still, no UK suppliers stock an SP1200 replacement display, so an order to the US was needed. Found one, but at a price around 4x the theoretical list price of the item (theoretical in the sense that you only get that price if you make a minimum order of 300). Oh, and a P&P charge that seemed more suitable for a lump of lead. And, oh x 2, UK import tax. And, oh x 3, and a charge from Royal Mail for the privilege of paying the UK import tax that was twice the cost of the tax! So that was about £35 and two weeks just to get the damm thing from A to B.

At least there is a happy ending. The new part arrived today, and I fitted it to the Emulator II+ in about 30 minutes. It's bright, clear, and works well. But, like the loading screen says, "This will take while"...

Oh and, as it turns out, LCD character displays from the 1980s weren't all that great anyway :-)

Emulator II+

Here are some pictures from back in December 2009, when I'd just bought an Emualtor II+. Came across these pictures again when working on an intermittent channel error on the machine (now solved, with some help from all the great people on the Yahoo Emulator II group). One of the ground pins on a demultiplexer chip was hanging out of its IC socket (more evidence of some frankly pretty shoddy restoration by a previous owner...).

Depeche Mode - Leave in Silence (1982)

The b-side is "Excerpt from My Secret Garden" - quite different to the album version, this version is instrumental, higher tempo, and some of the instrumentation is different. UK ebay: £1.20.

TR-606 bass drum pitch

Geoff Waterson's modification for TR-606 bass drum pitch, modifies the frequency of the fundamental (OSC 1) by varying R58. This leaves the 1st harmonic (OSC 2) unchanged. I think it might be cool to set things up so that the level, pitch, and decay of both oscillators could be varied.

Depeche Mode - See You (1982)

Their 4th UK single release. B-side: "Now this is fun". Bought on eBay for 99p.

Roland TR-606 bass drum schematic

As part of my 606 modification project, I decided to draw up this schematic of the bass drum circuit, using the free software ExpressPCB. On the basis of the equations from Thomas Michaux's hyperreal post, OSC 1 is at 60 Hz and quite short (Q = 7), whilst OSC 2 is at 130 Hz, even shorter (Q = 3), and with a lower amplitude (compare R36 with R60). You can hear it here. Various people have suggested pitch, decay, and other mods for this circuit. I'll be looking into those in a bit, but wanted to understand (and be able to retrieve) the original 606 BD sound. Accent is (I think) achieved by a higher voltage (and possibly longer) trigger pulse.

PC USB interface for Emulator II

Details have just been released of a DIY interface that allows transfer of samples via USB from a PC to an E-mu Emulator II. Great news! All I have to do now is get around to building it...